As software developers, all of us used at least one UML design tool such as Rational Rose, Enterprise Architect or even Microsoft VISIO. Those tools have one thing in common – they are commercial and thus cost money… I want to introduce you a nice free sequence diagram editor called SDEdit. It is not a full UML design editor, you can’t draw class diagrams or state diagrams, only sequence diagrams are there.

Markus Strauch, the author of this tool, also called it Quick Sequence Diagram Editor. The UML sequence diagrams are created from a textual syntax and not by drawing objects and lines. There is a text area at the bottom of the window to specify the objects and messages while you can see the sequence diagram itself at the upper part of the window.

There is a supports for actors, constructors, destructors, threads and on-diagram comments that can be used to represent conditions or loops. The aim of the tool is to save you from lots of the work that WYSIWYG applications require, when it comes to insert or remove objects and messages you just insert or remove a line of text and the tool will do all the rest. If there is a syntax error in your text, the first line where such an error occurs is highlighted and there will be a description of the error at the bottom of the window:

There is also multithreading support, so you can create diagrams that model arbitrarily many sequences running in parallel, not just a single one. The sequences can be distinguished by the colors of their corresponding lifeline.

The diagrams can be exported in various formats, including PDF, (E)PS, SVG, SWF, EMF, GIF, JPEG.

Go to SDEdit web page to read more and download the tool and its source code (yes, it is open source). What do you say? Isn’t it worth trying? I use this editor and find it very helpful, hope you will enjoy it as much as I do.